the vatican behind me, and there pope benedict's final public mass is now in the books. thousands of worshipers packed st. peter's basilica for the ash wednesday service, marking the start of lent. the retiring 85-year-old rode down the aisle in a wheeled platform, sparing him from having to walk. it's not easy for him these days. the pope made his exit in the basilica erupted in standing ovation. today we caught up with some tourists in st. peter's square all here to watch history unfold. >> in 600 years it hasn't happened. to be here is quite special. >> shepard: as the sun set on vatican city, thousands lined up for mass with the pope to receive their ashes and mark the start of length. >> we weren't going to come on ash wednesday because we figured the crowds would be crazy or nuts, but we figured it was a special day. it's ash wednesday. kind of planted it all in one and made it happened. >> shepard: many tourists planned their trips months in advance and learned about the pope's resignation only from messages from home. >> my mom e-mails me and said the pope resign